Method and apparatus of producing filling materials to be used together with hydraulic cements



May 1, 1956 Y LEJMARK 2,743,911

METHOD AND APPARATUS 0F PRODUCING FILLING MATERIALS TO BE USED TOGETHER WITH HYDRAULIC CEMENTS Filed Feb. 18. 1953 5 SheetsSheet l INVENTOR K e4 Poet-7 ZEJ/IAIFK ATTORNEY May 1, 1956 K. R. LEJMARK 2,743,911

METHOD AND APPARATUS OF PRODUCING FILLING MATERIALS TO BE USED TOGETHER WITH HYDRAULIC CEMENTS Filed Feb. 18, 1953 5 Sheets-Sheet 2 INVENTOR (AKA B05597 ZEf/f/IEK BY L am h ATTORNEY May 1, 1956 K. R. LEJMARK 2,743,911

METHOD AND APPARATUS OF PRODUCING FILLING MATERIALS 7 TO BE USED TOGETHER WITH HYDRAULIC CEMENTS Filed Feb. 18, 1953 3 Sheets-Sheet 5 BY a; 474 W/" ATTORNEY INVENTOR E) KARL 1908587 LEfN/l/QK United States Patent METHOD AND APPARATUS OF PRODUCING FILLING MATERIALS TO BE USED TO- GETHER WITH HYDRAULIC CEMENTS Karl Robert Lejmark, Timmernabben, Sweden Application February 18, 1953, Serial No. 337,604

Claims priority, application Sweden October 22, 1952 6 Claims. (Cl. 259-147) The present invention relates to the production of filling materials to be used together with hydraulic cements, such as Portland cement, for the manufacture of building materials. Such filling material is prepared by mixing wood waste, such as sawdust, cutter shavings and the like, with a small quantity of a hydraulic binding agent or lime, the quantity of waste products being for example 1-2% by volume or about by weight, the mixture being subjected to aeration and stirring so as to reduce the percentage of fatty acids and resins. The material is then stored for a sufliciently long time in order to effect so called autocombustiomand then the material thus treated is used as fillingmaterial when casting cement mortar, a product having good heat-insulating properties being thereby attained. Besides, the product is capable of being nailed. Thus, a sound absorbing, heat insulating and nailable underlayer flooring can be made of 1 part of Portland cement, 2 parts of sand and 2 parts of the filling material.

Hitherto, when preparing this filling material, the. wood waste has been mixed with lime or hydraulic cement in common concrete mixers or the like, and then shovelled by hand to suitable height in the neighbourhood of the mixer or transported from said mixer by conveyors of common type. Thus, mixing and conveyance from the mixer has been carried out in two steps.

It has now'been found, that the stirring and the aeration of the wood waste, which is a very important detail, as far as oxidation of the fatty acids and the resins included are concerned, are insufficient when a mixer of common type is used. The oxidation process is retarded and after the mixing has been carried out, the storing must be prolonged. The wood waste enclosed in the drum of the mixer, which for practical reasons must make up a comparatively large mass, prevents to a'great extent the supply of air into the drum and the subsequent conveyance from the mixer, if carried out by means of a conveyor of common type in which the material is conveyed by means of belts or buckets, will not be subjected to the necessary turning or stirring.

The present invention relates to a combined mixing, aerating, and conveying method by which the said disadvantages are eliminated.

According to the invention the wood waste and the binding agent are introduced into a sloping chute in which they are carried forward by conveying means at such a speed that the material introduced into the chute is simultaneously subjected to stirring and conveying. Preferably, the conveying means are carried forward at such a speed that they cut through the material intoduced into the chute. The amount of the binding agent added to the material in the chute is automatically controlled by the quantity of the wood waste material conveyed in the chute. From the chute the mixed material may be delivered to a screening drum and the material passing through the screen of the drum is carried away by the rotating movement of the drum.

An embodiment of an apparatus for carrying out the method according to the invention is illustrated in the accompanying drawings in which Fig. .l is a horizontal view of the apparatus, Fig. 2 is a view along the line IIII of Fig. 1 and Fig. 3 is a view along the line IIIIII of Fig. 1. Fig. 4 is a vertical section on a larger scale of part of Fig. 2 and Fig. 5 is a section along the line V--V of Fig. 4.

The wood waste, which preferably consists of sawdust, is introduced into the lower part of a conveyor comprising a sloping chute 1 provided with conveying means in the form of scrapers 2 which are arranged approximately at a right angle to the bottom of the chute 1 and which are fastened at a distance from each other to an endless chain 3 running in the bottom of the -chute 1'.- These' scrapers 2 are comparatively low in comparison with the sectional height of the chute 1. The chain 3 is driven by means of a motor 4 via a pulley 5. Above the chute 1 and in some distance from its lower part a container 6 for burnt lime is placed, in the bottom of which an outlet is provided which may be closed by means of a shutter 7. Said shutter is swingably mounted at the one end of the outlet and firmly connected with a plate 8 extending towards the bottom of the chute 1. By means of a sector formed part 9 the plate 8 may be locked in different positions. The sawdust is introduced into the chute to such a height that it fills the chute above the scrapers 2. The sawdust conveyed in the chute will actuate the plate 8 so that the shutter 7- opens more or less depending upon the quantity of the sawdust conveyed in the chute. The greater quantity of sawdust being conveyed in the chute the more the shutter 7 is opened and a greater quantity of lime is fed into the chute from the container 6. By means of the sector part 9 the shutter 7 may be adjusted in such a way that a greater or less quantity of lime is supplied to the same quantity of sawdust introduced into the chute. The addition of lime may, thus, be adjusted with relation to the moisture content and the particle size of the sawdust which factors determine said addition. As the scrapers 2 are embedded in the sawdust in the chute, the scrapers during the operation of the conveyor will cut through the material whereby said material is thrown about and mixed very effectively together with the lime added at the same time as an effective aeration and stirring is obtained.

The best efliciency is obtained with scrapers having a width of about 300 mm. and a height of about 50 mm. The scrapers are preferably made of sheet-iron of a thickness of about 2 mm. The distance between the scrapers ought to be about 500 mm. and the conveying chain ought to run at a speed exceeding 2 in. per second, for example 3 in. per second. A good mixing is obtained already when the length of the conveyor is 2 m.

On account of the speed at which the scrapers 2 work, the sawdust is flung out of the conveyor in such a manner that a spreading of the material favourable for the oxidation process can take place, before it falls down in the place intended.

In order to obtain an increased aeration of the sawdust a screening drum 10 is placed close to the outlet end of the chute 1. The sawdust is thrown into the drum 10 and after having been turned in the drum and passed the screen it falls down on a collecting plate 11 below the screening drum 10. The drum is provided with longitudinally extending laths 12 which at the rotation of the drum sweep the screened material away from the plate '11 to a hopper-shaped device 13 and further to a conveyor which is constructed in the same manner as the conveyor shown in Fig. 2 and which, thus, consists of a chute 14, in the bottom of which a chain 15 provided with scrapers 16 is running, by which the material is again thrown around and aerated before it is thrown out and spread in a suitable manner to the place intended.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

l. The method of simultaneously conveying and aerating a comminuted light weight material, such as wood waste, and mixing the same with a binding material, consisting in feeding the material to the bottom end of an inclined chute and subjecting the material to the impact of a succession of spaced, upwardly traveling scrapers, thereby producing upward movement of the material, causing the scrapers to travel at a speed above that assumed by the material and to cut through and thereby agitate the material in their passage, introducing into the moving and agitated stream of material a quantity of binding material to be mixed therewith, and utilizing the moving stream to determine the rate of addition of the binding material.

2. The method defined in claim 1 in which the added binding material is lime.

3. The method defined in claim 1 together with the further steps of screening the aerated and mixed material and then again feeding the screened material to the bottom end of an inclined chute, subjecting the material to the impact of a succession of spaced, upwardly traveling scrapers, and causing the scrapers to travel at a speed above that assumed by the material and to cut through and thereby agitate the material in their passage.

4. The method defined in claim 1 together with the further step of screening the mixed material and then subjecting the screened material to further agitation until the fatty acids and resins are thoroughly oxidized.

5. Apparatus for the manufacture of a filling material to be used together with hydraulic cements for the production of building material, comprising a sloping chute open at its lower part to receive material, an endless conveyor disposed in the chute and means to propel the conevyor upwardly in the chute, spaced scrapers on the conveyor, a container disposed over the chute immediately above said lower receiving part thereof and having an outlet in its bottom, a shutter for said outlet pivoted to the container on the lower side of the outlet transversely of the chute and adapted to swing open by gravity, an adjustable bafile plate pivotally attached to the underside of the shutter transversely of the chute with its free edge adapted to extend downwardly into the chute, and means to lock the baffle plate in adjusted angular position relative to the shutter.

6'. Apparatus as defined in claim 5 in which the said locking means for the bafile plate comprises a sector member attached to and extending down from the under side of the shutter concentrically with the pivot of the bafile plate, and means for releasably securing the baflle plate to the sector member in adjusted positions of the battle plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,473,445 Schumacker Nov. 6, 1923 2,031,369 Holbeck Feb. 18, 1936 2,264,170 Stancliife Nov. 25, 1941 2,533,852 Tietig Dec. 12, 1950 2,539,904 Hansen Jan. 30, 1951 2,557,623 Wenner June 19, 1951 

1. THE METHOD OF SIMULTANEOUSLY CONVEYING AND AERATING A COMMINUTED LIGHT WEIGHT MATERIAL, SUCH AS WOOD WASTE, AND MIXING THE SAME WITH A BINDING MATERIAL, CONSISTING IN FEEDING THE MATERIAL TO THE BOTTOM END OF AN INCLINED CHUTE AND SUBJECTING THE MATERIAL TO THE IMPACT OF A SUCCESSION OF SPACED UPWARDLY TRAVELING SCRAPERS, THEREBY PRODUCING UPWARD MOVEMENT OF THE MATERIAL, CAUSING THE SCRAPERS TO TRAVEL AT A SPEED ABOVE THAT ASSUMED BY THE MATERIAL AND TO CUT THROUGH AND THEREBY AGITATE THE MATERIAL IN THEIR PASSAGE, INTRODUCING INTO THE MOVING AND AGITATED STREAM OF MATERIAL A QUANTITY OF BINDING MATERIAL TO BE MIXED THEREWITH, AND UTILIZING THE MOVING STREAM TO DETERMINE THE RATE OF ADDITION OF THE BINDING MATERIAL. 